the gate is a small "valve" in the port side of the lift that you use to sink the lift when you go to launch the PWC. It is a guillotine type device that slides between a couple of rubber "o" rings creating a seal so, theoretically, when you evacuate the water in the lift it floats. I love the principle of the leisure lift but the gate, in my mind, is the weak point. Unless these are fairly new I would not pay $500.00. Why is the guy selling? He may be having the same problem I had. Again, my opinion is get a lift that is sealed and has rollers and tilts into the water and just motor on it. Good luck.:cheers: